Code division multiple access (CDMA) techniques are commonly used in communication systems, to allow communications between a large number of system users. Repeaters are used as an extension between mobile users and base stations in a variety of communication systems. Tower-top amplifiers are also used as an extension of many base station and repeater designs.
K. Gilhousen, R. Padovani, and C. Wheatley, Method and System for Providing a Soft Handoff in Communications in a CDMA Cellular Telephone System, U.S. Pat. No. 5,101,501 (Mar. 31, 1992) disclose a system for directing communications signals between a mobile user and cell sites, as the mobile user moves between cell site service areas.
K. Gilhousen, R. Padovani, and C. Wheatley, Diversity Receiver in a CDMA Cellular Telephone System, U.S. Pat. No. 5,109,390 (Apr. 28, 1992) disclose a spread spectrum receiver subsystem for utilization in a CMDA cellular telephone system.
D. Reudink, Narrow Beam Antenna Systems with Angular Diversity, U.S. Pat. No. 5,563,610 (Oct. 08, 1996) discloses a receiving system which includes at least one antenna providing a plurality of antenna beams. A first antenna branch processes a first plurality of signals within a first plurality of antenna beams. The first processing branch includes a plurality of delay paths, each receiving one of the first plurality of signals. The first processing branch also includes a combiner for combining the signals after output from the delay paths. A second antenna branch processes a second plurality of signals within a second plurality of antenna beams. The second processing branch includes a plurality of delay paths, each receiving one of the second plurality of signals. The second processing branch also includes a combiner for combining the signals after output from the delay paths. A CDMA receiver has a first port coupled to an output of the first processing branch, and a second port coupled to an output of the second processing branch.
R. Dean, F. Antonio, K. Gilhousen, and C. Wheatley, Dual Distributed Antenna System, U.S. Pat. No. 5,533,011 (Jul. 02, 1996) disclose a distributed antenna system for "providing multipath signals which facilitate signal diversity for enhanced system performance. Each node of the antenna at a common node provides a path having a different delay to the base station". While a "direct" connection is established between a distributed antenna system and a base station, wherein the distributed antenna system provides multipath signals (increasing the dimensionality) to facilitate signal diversity, the system does not disclose the use of diversity within a repeater system.
R. Dean, P. Antonio, K. Gilhousen, and C. Wheatley, Dual Distributed Antenna System, U.S. Pat. No. 5,513,176 (Apr. 30, 1996) disclose a distributed antenna system that is utilized in a system for "providing multipath signals which facilitate signal diversity for enhanced system performance. Each node of the antenna comprises more than one antenna. Each node at a common node provides a path having a different delay to the base station".
While prior art diversity techniques are typically used to expand system capacity, they fail to disclose the use of diversity within the primary antenna of a CDMA repeater or a tower-top amplifier.
While the prior art discloses the use of diversity for in-building applications relative to a base station, they fail to disclose delay techniques to provide diversity within an over-the-air CDMA repeater.
The disclosed prior art systems and methodologies thus provide basic distributed antenna systems, but fail to provide a diversity within a CDMA receive diversity system within an over the air repeater system, and also fail to provide delay combining diversity for a tower top or low noise amplification system. The development of such a repeater system would constitute a major technological advance.